Auxiliary propulsion unit



March 27, 1934. J. A. McGREW 1,952,271

AUXILIARY PROPULSION UNIT Filed NOV. 14, 1930 4 Sheets-Sheet 1 March 27, 1934. J McGREW AUXILIARY PROPULSION UNIT Filed Nov. 14, 1950 4 Sheets-Sheet 2 March 27, 1934. J, A. M GREW 1,952,271

AUXILIARY PROPULSION UNIT Filed Nov. 14, 1930 4 Sheets-Sheet s March 27, 1934. J. A. M GREW AUXILIARY PROPULSION UNIT Fiied Nov. 14, 1930 4 Sheets-Sheet 4 Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE 10 Claims.

The present invention relates to auxiliary propulsion units for locomotives and particularly to the means for effecting entrainment and disentrainment of the motor of the auxiliary propulsion unit to a load-bearing axle.

Various types of auxiliary propulsion units, designed to assist a locomotive in starting a heavy train or for assisting a locomotive when operating at low speed under a heavy load, have heretofore been designed or suggested, and several types of such unitsare now in commercial use. As the motor of the auxiliary propulsion unit is intended to function only when the locomotive itself is proceeding at low speeds, it must be operatively'connected to a load-bearing axle of the locomotive tender or other car of the train only when the train is proceeding at low speeds, and must be disconnected from the load-bearing axle for all higher speeds of the train. A type of entrainment mechanism heretofore used has comprised a gearing including a driving gear arranged to be driven by the motor of the auxiliary propulsion unit,. a driven gear mounted upon a load-bearing axle, and a tumbler gear supported in such manner as to be at all times in operative engagement with the driving gear but adapted to be moved into and out of operative engagement with the driven gear, the tumbler gear thereby constituting a movable element by means of which the operative connection may be established or broken.

In one type of such device the tumbler gear is mounted upon a rocker, which rocker is manipulated to describe an arc-shaped path about a pivotal support, stops being generally provided for limiting the movement of the rocker, and hence of the tumbler gear, in the direction in which it is moved to bring the tumbler gear into operative position. In my prior patent, No. 1,703,942, granted March 5, 1929, I suggest that the tumbler gear need notbe mounted upon a rocker but may be provided with trunnions which are free to run upon parallel trackways, entrainment of the tumbler gear being efiected automatically and almost wholly by the influence of tooth pressure when the motor of the auxiliary propulsion unit is started, and disentrainment being eifected automatically upon de-energization of the motor.

In both cases, however, it has been found in actual practice that trouble is sometimes met with due to the fact that, when in operative position, the tumbler gear is not so rigidly supported that its axis remains at all times exactly parallel to the axes of the driving and driven gears,

both types of devices referred to above, also, the' movement of the tumbler gear toward the driven gear is not limited in an accurate and definite manner, even where, in the case of the rocker, stops are provided to definitely limit the arouate travel of the rocker.

In accordance with the present invention, a novel form of entrainment mechanism is provided whereby entrainment and disentrainment may be readily effected but which, at the same time, insures that the tumbler gear, when it is in its operative or power transmitting position, is constrained to rotate about an axis which is exactly parallel with the axes of the driving and driven gears and which axis invariably assumes the same position whenever the tumbler is moved into operative position. Not only are the destructive results incident to non-parallelism of the axes of the tumbler and driving and driven gears avoided, but the present invention also insures that the teeth of the three gears mesh in exactly the right manner, thus minimizing wear and decreasing frictional losses.

In carrying out the invention I preferably provide a truck frame which has three pairs of bearings integral therewith and which bearings always retain the same definite relationship to each other. In one pair of spaced aligned bearings is mounted the crankshaft of the auxiliary propulsion unit, upon whichrshaft the driving gear is fixed, in the second pair of spaced aligned bearings is rotatably supported a load-bearing axle of the train, and the third pair is adapted to receive the axially extending cylindrical trunnions of the tumbler gear. The last mentioned bearings are open on one side so that the tumbler gear may be manipulated so that its trunnions are rotatably mounted in the bearings when the tumbler is in operative position, but may be readily removed from the bearings when it is desired to disentrain the motor from the loadbearing axle. This novel arrangement provides an absolutely rigid mounting for the tumbler gear when this gear is in its operative position, minimizes the liability of breakage to a member of thegear train, insures that the teeth of the gear mesh to the proper depth, and makes certain that the several gears will not be operatively connected at any time so as to rotate about axes which are not in exact parallelism.

The present invention further provides novel means for effecting the movement of the tumbler gear into and out of operative engagement with the driven gear and additional important and novel features of construction, as will be hereinafter set forth.

In the drawings is illustrated an auxiliary propulsion unit particularly adapted for installation on a locomotive tender truck having three axles and six wheels, and two specific forms of the novel gearing are disclosed. It will be understood, however, that, in adapting the invention for service in various positions, the design and arrangement of its component elements may be considerably modified, if desired, and also that the invention may be incorporated in an auxiliary propulsion unit of the four-wheeled type and adapted for use either in connection with a locomotive tender or other car of the train.

In the accompanying drawings the two forms of the invention which have been selected for illustration by way of example are fully shown and so much of the remaining detail of the auxiliary propulsion motor and the supporting truck as is necessary for an understanding of the invention.

Figure 1 is a top plan view of the truck, partly broken away to show the entrainment mechanism and means for actuating the same;

Figure 2 is a section on line 22 of Fig. 1;

Figure 3 is a similar section but showing the tumbler gear of the entrainment mechanism in a different position from that in which it is shown in Fig. 2;

Figure 4 is a section on line 4-4 of Fig. 3;

Figure 5 is a section on line 5-5 of Fig. 3;

Figures 6 and 7 are views somewhat similar to Figs. 2 and 3 but showing an alternative form of entrainment gearing, Fig. 6 showing the tumbler gear in disengaged position and Fig. '7 showing this gear in operative position; and

Figure 8 is a diagrammatic view showing the gearing in its operative condition.

The truck frame is indicated generally at 10 and the three axles upon which the frame is mounted at 11, 12, and 13, respectively. The specific construction of the frame and the means for supporting the frame upon the axles com prises no portion of the present invention and need not be specifically described. The frame of the auxiliary propulsion unit is indicated generally at 14, and a detailed description of this frame, and indeed of the steam operated motor which it supports, is not necessary for a full understanding of the present invention. The frame is supported at three points, that is, at spaced points upon the load-bearing axle 13 and also upon a transverse equalizer member 15, the ends of which are supported from the frame through intermediate springs and equalizing members indicated at 16. One cylinder of the auxiliary propulsion unit is indicated at 17, and it will be understood that there preferably are two of these cylinders, equidistantly spaced from the center line of the frame 14. The pistons, valves, etc., of the auxiliary propulsion unit are conventional and need not be referred to.

The spaced aligned bearings which are mounted upon axle 13 are indicated at 18, and from Figures 2 and 3 it will be seen that each of these bearings comprises a half portion 19, integral with the body of the frame 14, and a removable cap 26. A crankshaft is indicated at 21, this crankshaft being connected by suitable connecting rods to the pistons of the steam actuated motor and being rotatably supported in bearings generally indicated at 22, 22, each of these bearings having a half portion 23 formed integral with the frame 14. and a half portion 24 in the form of a cap which may be bolted to the frame.

Fixed on the load-bearing axle 13, at the midpoint thereof, is a driven gear 25, and fixed on crankshaft 21, at the midpoint thereof, is a gear 26, the teeth of gears 25 and 26 being equal in length and cross section. The hearings in which the axle 13 and the crankshaft 21 are rotatably supported are. so designed that the axes of these two members remain at all times in exact parallelism. In this embodiment the driven and driving gears are adapted to rotate in a clockwise direction as viewed in Figures 1 and 2, when the train is being driven forwardly.

The tumbler gear is indicated at 30, this gear being, in the form of the invention disclosed in Figures 1 to 5, inclusive, positioned above the driving gear 26. The tumbler gear 30 has axially extending trunnions 31, and projecting from the trunnions are axial pins or spindles 32. The tumbler gear is adapted to be moved, in the operation of the mechanism, from the position in which it is shown in Figure 2, which is the inoperative position, to the position in which it is illustrated in Figure 3, which is the operative position.

In moving from the inoperative to the operative position, the trunnions are caused to move downwardly along inclined spaced, trackways or guides 33, there being one of these inclined guides on either side of the tumbler gear. The trackways or guides are so inclined that, in moving from inoperative to operative position and vice versa, the teeth of the tumbler gear remain in constant mesh with the teeth of the driving gear. As the tumbler gear reaches its operative position, the trunnions thereof come to rest in half bearings 33 especially designed to rotatably support the trunnions, and hence the tumbler gear, during the operation of the auxiliary propulsion unit to assist the main power plant or locomotives The opensided or half bearings 33 are formed in webs 34 which comprise integral portions of the frame of the auxiliary, propulsion unit, and the axes of these open-sided bearings are coincident and parallel to the axes of crankshaft 21 and axle 13 so that, whenever the trunnions of the tumbler gear so are seated in these bearings, the axes of the gears 25, 26, and 30 are in parallelism.

The ,trackways 33 being inclined downwardly and toward the driven gear, it naturally follows that the tumblergear 30 will tend to move downwardly into operative position at all times. It is normally restrained from doing so by means of a lever pivoted at 41 to the frame, the lever extending upwardly from its point of pivotal support and then in a generally horizontal direction, as shown in Figures 2 and 3. The upper end of the lever is bifurcated or yoke-shaped, and the arms lie parallel to the end surfaces of the trunnions 31 and are provided with down-turned end portions e2 which are adapted to engage the axially projecting spindles 32 of the trunnions and to effect the withdrawal of the tumbler gear from its operative position when the lever is rocked in a counter-clockwise direction (Figures 2 and 3). Conversely, when the lever is moved in a clockwise direction, the tumbler is allowed to move into its operative position under the influence of gravity, or of the rotation of the driving gear 26.

The means for rockingthe lever comprises a longitudinally reciprccable rod 4 1- disposed axially of the frame and suitably supported in bearings, which rod is normally biased to move in a direction to effect disengagement of the tumbler gear ill) 30 and drivengear by means of a coiled spring 45, one end of which bears against an abutment 46 secured to the rod, and the other end of which rests against a bearing member 47 which forms one of the rod supports. :Upon the free end of rod i4 is a regulating valve or piston 48 which lies within a cylinder 49. This piston 48 is so designed and constructed that it normally closes the steamline from the source of steam supply to the cylinders of the auxiliary propulsion unit. A portion of this steam line isindicat'ed rather diagranunatically at 50, and the entry port-for the steam passing to the cylinders is indicated at 51.

Normally the flow of steam through the cylinders is cut off by a valve which may be conveniently located in the locomotive cab and is therefore not illustrated, and the regulating valve 48 occupies the position in which it is shown in Figure 2. When steam under pressure is allowed to pass through conduit 50, however, it strikes the plunger-like regulating valve 48 and forces it to the right (Figures 2 and 3), against the action of spring 45, until the valve reaches the position in which it is shown in "Figure 3, its forward face seating on an annular seat 52 formed interiorly of cylinder 49, thus arresting its forward movement. When in this position the tumbler gear is entrained, and no further interference is offered to the free passage of steamto the cylinders of the auxiliary propulsion unit.

From the above description it is apparent that the tumbler gear is only lowered so that its teeth can operatively engage the teeth of the driven gear when the operator has caused steam to flow from the source of supply toward the cylinders of the auxiliary propulsion unit. Inasmuch as the steam flowing to the motor is the motive power for eifecting movement of the tumbler gear 30, it is clear that the tumbler gear will be lowered to its engagement position sub stantially simultaneously with the initial :slow movement of the pistons of the motor. At the instant of meshing of the tumbler gear and the driven gear, therefore, the tumbler gear may be rotating, but very slowly, and hence the meshing or engaging action is facilitated.

During operation of the auxiliary propulsion unit the continued steam pressure in the steam line 50 continues to hold the regulating valve 48 in the position in which it is shown in Figure 3, but, as soon as the steam supply is cut off, the spring 4-5 immediately becomes active to rock the lever toward the left (Figure 2) and to withdraw the tumbler to its inoperative position. Dlsengagement of the'tiunbler is facilitated also by reason of the fact that, as soon as the steam is out off, the crankshaft and tumbler gear 30 immediately decelerate, whereas the driven gear continues to rotate at the same speed as before. The driven gear therefore tends to throw the idle tumblergear 30 out of mesh, and this assists in the rapid-disengagement or disentrainment of the gears.

In the modified form of the invention disclosed in Figures 6 and '7, the tumbler gear is positioned below the driving and driven gears and is moved upwardly into operative position instead of downwardly, as was the case with the form-of the invention first described. In this instance, the driven and driving gears are adapted to rotate in a counterclockwise direction as viewed in Figures 6 and F7, when the train is moving forwardly, or toward the left. Here again it will be seen that the tumbler gear trunnions are received in half bearings 60 when the tumbler gear 3.0 is in operative position. The axes of these hearings are coincident and parallel to the axes of the crankshaft 21' and axle 13 so that the axes of the driving gear 26', the driven gear 25, and the tumbler gear 30" are in accurate parallelism during the time that the tumbler gear is transmit ting the torque of the driving gear to the loadbearing axle.

Movement of the tumbler gear into operative position effected bya pusher member 61 on the end of a rod 62, horizontally disposed, which rod is adapted to slide in bearings 47 and 64 which are preferably integral with the frame. A coiled spring normally tends to keep rod 62 in the position in which it is shown in Figure 6, one end. of this .spring bearing on an abutment 46' se cured to the rod and the other end upon the abutment 4'7. To the free end of the rod is secured the regulating valve or plunger 48. The plunger or regulating valve 48' is 'reciprocated within its cylinder 4.9 by steam pressure, exact- 1y as explained in connection with the description of the form of the invention disclosed in T Figures 1 to 5, inclusive. When the steam is first turned on, the rod 61 is moved to'the right, and the tumbler 30 is pushed before it, the trim-.- nions 31' of the tumbler gear moving along the upwardly inclined trackways 65. .As soon as the teeth of tumbler gear 30 have entered partial mesh with the teeth of the driven gear 25', complete entrainment is efiected by tooth pressure, in substantially the same manner .as .set forth in my prior patent, No. 1,703,942, before .referred to.

So long as the motor isin operation, the tumbler gear 30' is maintained in its operative position by tooth pressure, the trunnions revolving in the bearings 60. As soon as the motor is de-energized, the spring 45' is active to retract the rod '62 and pusher 61. The driving gear 26 and tumbler gear 30' likewise slow down, the effect of which is to cause the tumbler gear to be forced out of mesh by the driven gear 25, which naturally maintains its speed of rotation. As soon as disentrainment is effected, tumbler gear 30 falls to the position in which it is shown in Figure 6 and occupies such position until steam is again caused to flow to the motor.

In this instance, as well as in the form of the invention first described, the bearings for the crankshaft 21"and axle 13" are formed integral with the frame, at least half of each of these hearings is so formed, and the half bearings for the trunnions of the tumbler gear are formed in webs 65 likewise integral with the frame. As a result of forming the bearings for the crankshaft, driven axle, and tumbler gear in .a single rigid frame, the axes of the three gears are maintained rigidly in exact parallelism while the gears are actually engaged in transmitting power from the motor to the driven axle. This prevents unequal wear of the teeth, thereby pro longing the life of the unit and at the same time practically eliminating failures of the gearing.

While two forms of the invention have been illustrated and described in detail, one skilled in the art would readily appreciate that still fur ther forms may be conveniently devised and that also, in adapting the invention to various working conditions, the design and arrangement of parts can be widely varied.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, and gearing for operatively connecting the motor to a loadbearing axle, said gearing including driving, driven, and tumbler gears, the tumbler gear having axial trunnions, bearings fixed with respect to the axis of the driven gear for receiving and rotatably supporting the trunnions of the tumbler gear when the tumbler gear is moved into full meshing engagement with the driven gear, and means separate from the trunnioned tumbler gear member adapted to be brought into operative contact with said member to control the action thereof.

2. An auxiliary propulsion unit comprising a frame, a motormounted on the frame, and gear ing for operatively connecting the motor to a loadbearing axle, said gearing including driving, driven, and tumbler gears, the tumbler gear having axial trunnions, the frame having bearings in which the driving and driven gears are mounted to rotate about spaced parallel axes, means for supporting the trunnions of the tumbler gear so that it may be moved into and out of operative relationship to the driven gear while remaining in mesh with the driving gear, spaced open bearings to receive and rotatably support the trunnions of the tumbler gear when the tumbler gear is in operative engagement with the driven gear, the axis of these last mentioned bearings being parallel to the axes of the driving and driven gears, and fixed relatively thereto, and power actuated means adapted to be brought into operative contact with said tumbler gear and trunnion member for controlling the movement thereof.

3. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, and gearing for operatively connecting the motor to a load-bearing axle, said gearing including driving, driven, and tumbler gears, the driving and driven gears being mounted in the frame to rotate about fixed parallel axes and the axis of said tumbler gear being above that of the driving gear, means for supporting and guiding the tumbler gear so as to permit movement thereof downwardly toward and into operative engagement with the driven gear, and a lever adapted to be brought into operative engagement with said tumbler gear to prevent said movement toward said driven gear and to withdraw said tumbler gear from engagement with said driven gear.

4. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, and gearing for operatively connecting the motor to a load-bearing axle, said gearing including driving, driven, and tumbler gears, the driving and driven gears being mounted in the frame to rotate about fixed parallel axes and the axis of said tumbler gear being above that of the driving gear, means for supporting and guiding the tumbler gear so as to permit movement thereof toward and into operative engagement with the driven gear, trunnions on said tumbler gear, and a pivoted bifurcated lever, the arms of which are adapted to be brought into engagement with said tumbler gear to prevent said movement toward said driven gear and to withdraw said tumbler gear from engagement with said driven gear.

5. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, and gearing for operatively connecting the motor to a loadbearing axle, said gearing including driving,

driven, and tumbler gears, the driving and driven gears being mounted in the frame to rotate about fixed parallel axes and the axis of said tumbler gear being above that of the driving gear, means for supporting and guiding the tumbler gear so as to permit movement thereof toward and into operative engagement with the driven gear, trunnions on said tumbler gear, and a pivoted bifurcated lever, the arms of which are provided with hooked ends which are adapted to be brought into engagement with said tumbler gear to prevent said movement toward said driven gear and to withdraw said tumbler gear from engagement with said driven gear.

6. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, and gearing for operatively connecting the motor to a load-bearing axle, said gearing including driving, driven, and tumbler gears, the driving and driven gears being mounted in the frame to rotate about fixed parallel axes and the axis of said tumbler gear being above that of the driving gear, means for supporting and guiding the tumbler gear so as to permit movement thereof downwardly toward and into operative engagement with the driven gear, a lever adapted to be brought into operative engagement with said tumbler gear to prevent said movement toward said driven gear and to withdraw said tumbler gear from engagement with said driven gear, spring retracted means for operating said lever to withdraw and retain said tumbler gear, and fluid actuated means for releasing said spring actuated means for effecting engagement of said tumbler gear with said driven gear.

7. An auxiliary propulsion unit comprising, in combination, a frame, a motor mounted on the frame, gearing for operatively connecting the motor to a load-bearing axle, said gearing in cluding driving and driven gears and a tumbler gear unit adapted to move into and out of engagement with said driven gear, the driving and driven gears being mounted in the frame to rotate about fixed parallel axes, said tumbler gear unit comprising an idler gear and axially aligned trunnions, axially aligned open bearings rigid with said frame to receive said trunnions and rotatably support them when said idling gear is in full operative engagement with the driven gear, means for supporting and guiding said trunnions durin movement of said tumbler gear unit toward and from said driven gear, and a separate power operated member adapted to be brought into contact with said tumbler gear unit and to effect certain of its movements.

8. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, gearing for operatively connecting the motor to a loadbearing axle, said gearing including driving, driven, and tumbler gears, the driving and driven gears being mounted in the frame to rotate about fixed parallel axes and the tumbler gear having axially aligned trunnions, axially aligned open bearings, rigid with the frame, to receive said trunnions and rotatably support them when the tumbler gear is in full operative engagement with the driven gear, said bearings being below the axis of the driving gear and the axis of said bearings being parallel to the axes of the driving and driven gears, spaced trackways upon which the tumbler gear trunnions rest, said trackways being upwardly inclined toward the driven gear, and means for moving the tumbler gear upwardly along said trackways into operative position.

9. An auxiliary propulsion unit comprising a frame, a motor mounted on the frame, gearing for operatively connecting the motor to a loadbearing axle, said gearing including driving, driven, and tumbler gears, the tumbler gear having axial trunnions, bearings fixed with respect to the axis of the driven gear for receiving and rotatably supporting the trunnions of the tumbler gear when the tumbler gear is moved into fullmeshing engagement with the driven gear, means separate from the trunnioned tumbler gear member adapted to contact and control the movement of said member, and means under the control of the steam supply for said motor for operating said first named means.

10. In an auxiliary propulsion unit, in combination, a frame, a motor mounted on the frame, bearings in said frame for a load-bearing axle and a crankshaft, a crankshaft and an axle mounted in said bearings respectively for rotation about parallel axes, a driving gear mounted on the crankshaft, a driven gear mounted on the axle, a tumbler gear having aligned axial trunnions, and spaced aligned substantially semi-circular open bearings on the frame in which said trunnions are adapted to seat when the tumbler gear is in full operative engagement with the driven gear, and from which said tumbler and trunnion may be readily removed in dismantling the gearing, a steam actuated plunger adapted to directly effect abutting engagement with the tumbler gear, and means for causing said plunger to move said tumbler gear into entrainment with said driven gear.

JOHN A. MCGREW. 

